Job Offer- how long is acceptable

Hi There,

I have been through the interview process and have verbally been offered an Job on Island.
I have been waiting for the offer letter and Relo package now for about 2 months, how long is acceptable.
In Europe there is a quicker pace of life so I do appreciate I will need to change my expectations but is 2 months a little long? I have a few mails in between but it seems to be going nowhere slowly.
When do you cut your loses and move on?

Many Thanks